Movable cutting edge

ABSTRACT

A cutting edge for earth moving equipment, the cutting edge being movably supported so as to be independently movable to change a position of the cutting edge.

TECHNICAL FIELD

[0001] This invention relates generally to earthmoving equipment, and more particularly to a cutting edge that is movable to facilitate the loading and moving of earth or other materials.

BACKGROUND

[0002] In a scraper, as one example of an application of the present invention, the conventional cutting edge is fixed relative to the scraper bowl. Thus, the cutting edge cannot be raised or lowered other than by moving the entire scraping bowl up and down. Since it is not possible to move the cutting edge relative to the scraper bowl, the operator has to move the entire scraper bowl up or down to change the position of the cutting edge. This is extremely inefficient, and it detracts from the performance of the scraper. The same problem occurs in other types of earth moving equipment having a cutting edge.

[0003] U.S. Pat. No. 3,660,914 to Bechman et al. is entitled LIFT AND LOCK STRUCTURE FOR SCRAPER BLADE ASSEMBLY. Beechman et al.'s lift and lock structure facilitates control of the depth of the spread or fill during material unloading. The lift and lock structure could not be used to load material and would most likely be damaged if loading were attempted. Further, the lift and lock structure is limited to use as an attachment to the rolling floor of an elevated scraper, and could not be used on other types of scrapers. The lift and lock structure is a relatively light design for use only with small loads.

[0004] The present invention is intended to improve the effectiveness of the cutting edge and the overall efficiency of the device using such a cutting edge.

SUMMARY OF THE INVENTION

[0005] In one aspect of the present invention, a cutting edge for earth moving equipment is movably supported so as to be independently movable to change a position of the cutting edge.

[0006] In another aspect of the invention, a cutting assembly includes a movably supported cutting edge, and a driver operatively connected to the cutting edge that changes a position of the cutting edge.

[0007] In another aspect of the invention, an earth moving apparatus includes an implement, a cutting edge movably supported relative to the implement, and a driver operatively connected between the implement and the cutting edge to change a position of the cutting edge relative to the implement.

[0008] In another aspect of the invention, a method of operating an earth moving apparatus having an implement and a cutting edge movably supported relative to the implement includes changing a position of the cutting edge without requiring a corresponding change in position of the implement.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a perspective view of a scraper bowl having a cutting edge according to one embodiment of the present invention;

[0010]FIG. 2 is a partial schematic view showing a force distribution and a control system for controlling the variable pitch cutting edge; and

[0011]FIG. 3 is a partial perspective view of a cutting edge according to another embodiment of the present invention.

DETAILED DESCRIPTION

[0012] The cutting edge of the present invention may have the same or different basic dimensions and location as a stationary (fixed) cutting edge. This description is relative to a scraper, but as mentioned above, the cutting edge could be employed in other devices as well, such as by way of example only, bulldozers, loader buckets or other earth moving equipment having an implement with a cutting edge.

[0013]FIG. 1 is an example of one embodiment of the invention, in which the cutting edge 102 is pivotally attached to the scraper bowl 101, so that the cutting edge can be independently moved up and down.

[0014] By way of example only, the cutting edge 102 can be moved up and down by a hydraulic mover, such as a hydraulic cylinder 201, as shown in FIG. 1. Alternatively, a different force generating device could be used to move the variable pitch cutting edge 102 up and down, such as a gear drive or a cam, for example.

[0015] Control over the hydraulic cylinder 201 (or other device for moving the cutting edge 102 up and down) could be performed manually (for example, by the operator observing a position indicator) in a simple system, or it could be performed under computer control. As one example of a computer controlled system, FIG. 2 shows a sensor 301, a pump 302, a computer 303 and an operator interface 304. For example, the sensor 301 might send a signal to the computer 303 indicative of the amount of extension of the hydraulic cylinder (and therefore also the position of the variable pitch cutting edge 102). The computer 303 could control operation of the pump 302 which drives the hydraulic cylinder 201 to raise or lower the variable pitch cutting edge 102, based on the signal output from the sensor 301. An operator could control the computer 303 from the operator interface 304 connected to the computer 303.

[0016] The cutting edge would make the scraper (or other cutting equipment) a more efficient machine by introducing a second force into the cutting edge while digging. A primary cutting force for scraper cuts is shown as F1 in FIG. 2. A secondary force that would be introduced by the variable pitch cutting edge is shown as F2 in FIG. 2. The secondary force F2 (generated by extending the hydraulic cylinder 201 downwardly in FIG. 2) would lift the material being loaded. This lifting force would produce cracks in the material. How far the cracks would propagate ahead of the cutting edge would depend on the type of material being cut. Once fractured, the primary cutting force F1 would not need to be as large to load the material. This would improve fuel consumption and cycle times, making the scraper a more efficient machine. The computer 303 could be programmed to automatically adjust the pitch of the cutting edge based on sensing the force F1, or it could be adjusted manually by the operator. The computer 303 might control the cutting edge to oscillate or vibrate. For example, as the scraper bowl 101 is moved along the ground, the cutting edge 102 could be moved up and down at a predetermined speed relative to the bowl 101 to fracture the ground ahead and to place it under the next section of uplifted earth.

[0017]FIG. 3 shows a second embodiment of the present invention, in which a cutting edge 402 is slidably supported, and cams 400 move plungers 405 which in turn move the cutting edge 402 up and down in the plane of the surface of the cutting edge 402. A force F1 is the primary cutting force, as described above, and a secondary force F2 is downward in the direction in which the cutting edge 402 moves. The cutting edge 402 can be extended (and retracted) by operation of the cams 400, independently of movement of an implement 410 to which it is attached, as in the previous embodiment. Further, the fracture energy can be reduced since the cutting edge 402 can be operated independently of the implement 410 to act as a wedge to break up the work surface before it is lifted or moved by the implement 410. The cutting edge 402 could be made to oscillate or vibrate as in the previous embodiment, and the same type of control system as shown in FIG. 2 (or any other appropriate control system, such as a manual control system, for example) could be used with this embodiment as well.

[0018] Industrial Applicability

[0019] The operator of the scraper could be given control of the cutting edge via the operator interface 304. In circumstances where fine grading is required, the operator would no longer have to move the entire implement (such as the scraper bowl 101), which is typically relatively heavy, up or down to adjust the amount of material being cut. The operator could manually adjust the position of the variable pitch cutting edge 102/402 instead, or it could be done automatically under control of the computer 303. This would be faster and require less force than moving the entire implement.

[0020] As described above, the movable cutting edge of the present invention is not limited to use in any one type of earth moving apparatus. Making the cutting edge adjustable improves the cutting operation as well as making the device in which the cutting edge is used more economical. 

What is claimed is:
 1. A cutting edge for earth moving equipment, wherein the cutting edge is movably supported so as to be independently movable to change a position of the cutting edge.
 2. The cutting edge recited in claim 1, wherein the cutting edge is pivotally supported.
 3. The cutting edge recited in claim 1, wherein the cutting edge is slidably supported.
 4. A cutting assembly, comprising: a movably supported cutting edge; and a driver operatively connected to said cutting edge that changes a position of said cutting edge.
 5. The cutting assembly recited in claim 4, wherein said cutting edge is pivotally supported, and said driver includes a hydraulic mover that changes an inclination of said cutting edge.
 6. The cutting assembly recited in claim 4, wherein said cutting edge is slidably supported, and said driver includes a cam that changes an extension amount of said cutting edge.
 7. The cutting assembly recited in claim 4, further including a sensor connected to said driver that senses a condition of said driver from which the position of said cutting edge is determined.
 8. The cutting assembly recited in claim 5, further including a pump connected to said hydraulic mover, a sensor connected to said hydraulic mover that senses a condition of said hydraulic mover, and a computer that controls operation of said pump based on the condition of said hydraulic mover sensed by said sensor.
 9. The cutting assembly recited in claim 4, wherein said driver is operative to change the position of said cutting edge so that said cutting edge oscillates or vibrates.
 10. An earth moving apparatus, comprising: an implement; a cutting edge movably supported relative to said implement; and a driver operatively connected between said implement and said cutting edge to change a position of said cutting edge relative to said implement.
 11. The earth moving apparatus recited in claim 10, wherein said cutting edge is pivotally supported.
 12. The earth moving apparatus recited in claim 10, wherein said cutting edge is slidably supported.
 13. The earth moving apparatus recited in claim 10, further including a computer programmed to control the position of said cutting edge in accordance with a primary cutting force.
 14. A method of operating an earth moving apparatus having an implement and a cutting edge movably supported relative to the implement, comprising: changing a position of the cutting edge without requiring a corresponding change in position of the implement.
 15. The method recited in claim 14, wherein said changing step includes changing an inclination of the cutting edge.
 16. The method recited in claim 15, wherein the inclination is changed based on a force used to cut the work surface with the cutting edge.
 17. The method recited in claim 14, wherein said changing step includes changing an amount of extension of the cutting edge.
 18. The method recited in claim 17, wherein the amount of extension is changed based on a force used to cut a work surface with the cutting edge.
 19. The method recited in claim 14, wherein the position of the cutting edge is changed in said changing step to cause an oscillatory or vibratory motion of the cutting edge. 